Papermaking machine



Sept. 30, 1969 c. L. SANFORD PAPERMAKING MACHINE 2 SheetsSheet 1 FiledJan. 27, 1965 nv mam Sept. 30, 1969 c. L. SANFORD 3,470,063

PAPERMAKING MACHINE Filed Jan. 27, 1965 2 Sheets-Sheet United StatesPatent 3,470,063 PAPERMAKING MACHINE Charles L. Sanford, Memphis, Tenn.,assignor to Kimberly-Clark Corporation, Neenah, Wis., a corporation ofDelaware Filed Jan. 27, 1965, Ser. No. 428,516 Int. Cl. D21f 1/10, 11/06US. Cl. 162--303 2 Claims ABSTRACT OF THE DISCLOSURE My inventionrelates to papermaking machines and more particularly to such machinesof the type in which substantial dewatering of the stock in forming ofthe web is accomplished by applying tension on the forming fabric orwire carrying the paper web to be dewatered as the forming fabric passesabout a curved surface.

It has previously been prosposed in the application of Charles A. Lee etal., Ser. No. 161,058, filed Dec. 21, 1961 (now Patent No. 3,224,928,issued Dec. 21, 1965); and in an application of John B. Graham, Ser. No.419,765 filed Dec. 21, 1964, now Patent No. 3,400,045, that a paper webmay be formed by directing a paper stock slurry between a so-calledbreast roll and a socalled slice roll which carry a forming wire, thewire extending around both rolls including a substantial arc of theslice roll and bridging a gap provided between the two rolls, and thestock being directed on to the portion of the wire bridging these tworolls. A top felt passes around the slice roll so that the paper webbeing formed lies between the wire and felt on this roll, and the web isdewatered primarily due to the force of the wire bearing on the roll andbeairng on the web and felt between the wire and roll, the force of thewire being due to the tension applied on to the wire. Although some ofthe water from the web is thrown from the wire as it passes around theslice roll due to centrifugal force, some of it remains and collectswithin the interstices of the wire and on the outer surface of the wire.

It is an object of the present invention to provide mechanism forremoving at least some of the water remaining in the interstices of theforming wire and on the outer surface of the wire so that dewatering ofthe web is more complete as it passes around the slice roll.

In brief, this object may be accomplished according to the teaching ofthe invention by providing a porous surfaced roll having contact withthe outer surface of the forming wire on the part of the wire supportedby the slice roll, with the porous surfaced roll acting to collect andremove a portion of the water clinging to the forming wire. Alternately,in lieu of the porous surfaced roll, a porous belt may be put intocontact with the surface of the forming wire; and, if desired, the beltmay be made to wrap a portion of the slice roll so as to applyadditional pressure on to the web formed around the slice roll andprovide additional dewatering action on the web.

The invention consists of the novel constructions, arrangements anddevices to be hereinafter described and claimed for carrying out theabove stated objects, and such other objects as will be apparent fromthe follow- Patented Sept. 30., 1969 ing description of preferred formsof the invention, illustrated with reference to the accompanyingdrawings, wherein:

P16. 1 is a diagrammatic elevational view of a papermaking machinehaving a wet end section embodying the principles of the invention; and

FIGS. 2 and 3 are diagrammatic elevational views of modified wet endsections which may be used in lieu of the wet end section of the machineillustrated in FIG. 1.

Like characters of reference designate like parts in the several views.

Referring to FIG. 1 of the drawings, the papermaking machine thereinillustrated may be seen to comprise a loop of web forming fabric or wire20 which is disposed about rolls 21, 22, 23, 24, 25, 26, 27, 28 and 29.The fabric 20 is a conventional paper web forming fabric or wire for usein Fourdrinier machines made up of interwoven warp and shute filamentsfor providing drainage openings therebetween through which water maydrain from dilute paper stock applied on the fabric. The strands may beeither metal or synthetic material in accordance with well-knownpractice. The roll 21, which is relatively large in diameter incomparison with the other rolls, may be termed a slice roll; and theroll 29, which has its center located appproximately above the center ofthe roll 21 and which is somewhat smaller in diameter than the roll 21,may be termed a breast roll. The roll 22 is a couch roll and has bothends fixed; and the rolls 23, 24, 27 and 28 are simple turning rollshaving both ends fixed. The roll 25 may be used as a stretch roll withconventional mechanism (not shown for simultaneously adjustably movingboth ends of the roll and maintaining the fabric 20 taut about therolls. The roll 26 is a conventional guide roll having one end fixed andthe other end movable; and any suitable conventional apparatus (notshown) may be connected with the movable end of the roll 26 so that theroll 26 functions to maintain the fabric loop 20 traveling insubstantially the same path about the rolls supporting the fabric. Oneor more of the fabric supporting rolls, such as the slice roll 21 or thecouch roll 22, may be driven for the purpose of driving the fabric 20,so that the fabric travels over the fabric supporting rolls, all ofwhich turn.

It will be observed that the fabric 20 passes around the roll 29 andbridges the rolls 21 and 29, which have a slight gap between them, andthen passes around the roll 21, covering an arc of about of the roll 21.The fabric 20 then passes in a direct path to the couch roll 22, aroundthe roll 22, beneath the roll 23, over the roll 24, beneath the roll 25,over the roll 26, and over the upper peripheral surfaces of the rolls 27and 28. Any suitable doctors and water showers may be used in connectionwith the fabric 20 and with the rolls supporting the fabric, such as thedoctors 30, 31 and 32, and the showers 33, 34 and 35. All of the rollssupporting the fabric 20, including the rolls 21 and 29, may be of solidconstruction as distinguished from hollow perforated construction,although the roll 22 is preferably provided with narrow circumferentialwater receiving grooves in its peripheral suface.

An upper loop of fabric 36 is disposed about rolls 37, 38, 39, 40, 41,42, 43, 44, 45, 46, 47, 48, 49, 50 and 51, in addition to the rolls 22and 21. The fabric 36 is preferably one that absorbs water to a greaterextent and releases water more easily than does the usual Fourdrinierwire and may be a conventional top felt used by paper makers. The fabric36 is in direct contact with the exterior surface of the slice roll 21,and the fabric 20 lies on top of or outside of the fabric 36 as thefabric 36 passes over the roll 21. The rolls 46, 48 and 51 arepreferably suction rolls as illustrated, and the other roll may besolid.

The roll 42 is a conventional stretch roll having both endssimultaneously adjustably movable by suitable adjusting mechanism (notshown) for maintaining the loop of fabric 36 taut about the rollssupporting the loop. The roll 40 is a conventional guide roll having oneend fixed and the other end movable under the control of any suitablecontrol mechanism (not shown) for maintaining the fabric 36 traveling ina predetermined path about the rolls supporting the fabric. The rolls 46and 48 are pressure rolls, and each of these has a pressure nip with asteam heated Yankee drier 52 of conventional construction. Crepingdoctors 53 and 54 are provided for creping paper web from the surface ofthe Yankee drier 52, the doctors 53 and 54 being alternately sooperable. The roll 51 constitutes one roll of a main press 55 which alsoincludes a roll 56 having a pressure nip with the roll 51. A roll 57 ispreferably provided in connection with the roll 22 for holding thefabrics 20 and 36 firmly in contact on the surface of the couch roll 22.The other rolls 37, 38, 39, 41, 43, 44, 45, 47, 49 and 50 supporting thefabric 36 are simple turning rolls. Any of the rolls supporting the felt36, such as the roll 21, may be driven for moving the felt about itssupporting rolls.

The wire 20 and the felt 36 travel as a sandwich, that is, the wire 20and fabric 36 are in contact in their path of travel about the roll 21and from thence to the roll 22. A third fabric loop 58 passes betweenrolls 51 and 56. The fabric 58 is preferably a bottom feltconventionally used in papermaking. The fabric 58 passes around rolls59, 60, 61, 62, 63, 64, 65 and 66, in addition to the roll 51. The roll66 constitutes one roll of a wringer 67 which includes also another roll68 held to have a pressure nip with the roll 66. The roll 64 is aconventional guide roll having one end fixed and the other end movableunder the control of a suitable control mechanism (not shown) formaintaining the fabric 58 traveling in a predetermined path about therolls supporting the fabric. The roll 61 is a conventional stretch rollhaving both ends simultaneously adjustably movable by suitableadjustable mechanism (not shown) for maintaining the loop 58 taut aboutthe rolls supporting the loop. The other rolls 59, 60, 62, 63 and 65 aresimple turning rolls.

A stock inlet 69 is provided for directing paper stock between the rolls29 and 21 and particularly on to the portion of the fabric 20 thatbridges the narrow gap between the rolls 21 and 29. The inlet comprisesa pair of plates 70 and 71 which have facing parallel flat surfacesdefining an elongated slot between them. The plates 70 and 71 arehorizontal, so that stock discharges between them through the slotdefined by the plates horizontally into the nip between the rolls 21 and29.

The fabric 20 and felt 36 leave the surface of the roll 21 along a line72 on the surface of the roll 21 that is parallel with the axis of theroll 21. A roll 73 is in contact with the fabric 20 as it passes aroundthe slice roll 21 along a line 74 which is slightly spaced from orimmediately ahead of the line 72 on the surface of the roll 21.

The roll 73 may be made to simply have a non-forceful contact with thewire 20 or may be made to bear on the roll 21 and thereby on the wire 20with a substan tial force such as, for example, up to 50 pounds perlineal inch, so that the roll 73 acting in conjunction with the roll 21functions somewhat as a press, squeezing water from the paper webpassing between the rolls 73 and 21. The roll 73 is provided with aporous surface. The roll 73, for example, may be hollow and may beprovided with an array of holes drilled through its peripheral surface;alternately, the roll 73 may be solid and may be provided withcircumferential grooves or with an indented thread in its surface. Asanother alternative, the roll 73 may be solid and may be provided with ajacket about its peripheral surface made of a wire similar to the wire20 with interwoven warp and shute filaments providing intersticesbetween them. If grooved or threaded, the grooves or thread may, forexample, be .025 inch wide with .100 inch lands between the grooves orturns of the thread, and the grooves or thread may have a A inch depth,for example.

A water shower 77 and a pair of suction boxes 78 and 79 in contact withthe fabric 36 are preferably provided above roll 45 for cleaning thefabric, for removing fines from the fabric so that it is not plugged bythe fines, and for dewatering the fabric whereby it is presented to theroll 21 in a clean, relatively dewatered condition.

In operation, paper stock slurry is supplied to the inlet 69, and thepaper stock passes through the slot between the parallel plates 70 and71 and discharges horizontally into the gap between the rolls 21 and 29and on to the portion of the fabric 20 bridging the gap between theserolls. The plates 70 and 71 may, for example, be 8 inches to 30 incheslong and may be spaced less than an inch apart, such as inch to inch, soas to impart a fine scale turbulence to the stock passing between them,in accordance with the teachings in the copending application of DavidW. Appel et al., Ser. No. 278,521, filed May 2, 1963, now abandoned. Thepaper stock starts to drain immediately on contact with the wire 20; andthe stock passes, as it forms into a web, around the roll 21, beingdisposed between the felt 36 and wire 20. The web in passing around theroll 21 in a sandwich between the wire 20 and felt 36 is dewateredprimarily due to the force with which the wire bears on the roll 21 andon the intermediate web and felt 36 because of the tension maintained onthe wire around the roll, although centrifugal force also helps indewatering. The Water from the web being formed between the wire 20 andfelt 36 about the surface of the roll 21 passes outwardly into theinterstices of the wire 20 and tends to cling to the outer surface ofthe wire. Centrifugal force in particular is effective tending tooutwardly throw the water in the interstices of the wire 20 or clingingto the wire or at least keeping the water draining from the stock withinthe interstices of the wire 20 as it passes about the roll 21, ratherthan permitting the water to be reabsorbed into the felt and paper web.The water will re-enter the web and the felt 36, if permitted,particularly at or beyond the place of separation of the wire and feltalong the line 72 at which centrifugal force is no longer effective.

Assuming that the roll 73 is made to forcefully bear on the roll 21, theroll 73 squeezes water from the paper 'Web passing between the rolls 73and 21 and densifies the web. The roll 73, due to its porosity, alsofunctions, whether it has a forceful or non-forceful nip with the roll21, to remove all or a part of the free water exising within theinterstices of the wire 20 or clinging to the wire 20 prior to the line72 at which the wire 20 and felt 36 leave the slice roll 21 and beyondwhich the feltweb-wire sandwich is not subject to centrifugal force dueto traveling around the center of the roll 21. The free water within theinterstices of the wire 20 or otherwise carried by the wire enters intothe threaded grooves or drillings of the porous surfaced roll 73, orinto the interstices of the wire jacket provided on the roll 73, and theroll 73 attracts this water and removes is from the wire; and the wateris subsequently thrown outwardly from the surface of the roll 73 due tocentrifugal force as the roll 73 rotates. If desired, in order to assistin removing the water from the roll 73, an air doctor 75 or a wipe 76,or both air doctor and wipe similarly effective, may be provided on theroll 73. The air doctor 75 may simply constitute a plurality of jets oran elongated slot directing air under pressure on the surface of theroll 73, and the wipe 76 may simply constitute a slab of flexiblematerial riding on the surface of the roll 73.

The web continues along with the wire 20 and felt 36 to the rolls 22 and57, and the wire 20 separates from the felt 36 at this point, the paperweb continuing with the felt 36 and traveling on the underside of thefelt. The web follows the felt 36 rather than the wire 20 at this place,since the felt is considerably more dense than the wire.

The felt and Web travel through the main press 55, and the press 55 iseffective to press some of the remaining water from the web traveling onthe underside of the felt, and this dewatering action is augmented bythe bottom felt 58 which functions to absorb water from the web as theweb passes through the press. The felt 36, continuing to carry the webon its under surface, passes around the rolls 50 and 49 t0 the pressureroll 48, and the web transfers from he felt 36 on to the drier drum 52in the nip between the roll 48 and the drum 52. As the drum 52 rotates,the web is carried on the outer surface of the drum through the nipbetween the pressure roll 46 and the drum; and the pressure roll 46 alsohas a dewatering action on the web and causes sure adherence of the webon the drum 52. The Web in traveling with the drum 52 to the doctorblades 53 and 54 is dried, and one or the other of the blades 53 and 54doctors the web from the drum 52. The web is then reeled into rolls byany suitable reeling equipment (not shown).

The porous roll 73 advantageously removes free water clinging to theouter surface of the wire 20, or water within the interstices of thewire 20, so that the water cannot reenter the paper web between the wire20 and the felt 36, particularly as the wire 20 and felt 36 leave theslice roll 21 along the line 72 located adjacent to the roll 73.Therefore, there is less water that must be removed from the paper webby the main press 55, by the rolls 46 and 48 pressing the web betweenthem and the drier durm 52, or by the drum 52 itself due to its dryingaction. The web also is drier at the line of pickup, at which the wire20 separates from the paper web and felt between the rolls 22 and 57,thus reducing danger of disturbances to the wet web at this point.

The wet end section of the papermaking machine illustrated in FIG. 2 maybe used with the same press section and drying section illustrated inFIG. 1, and differs principally from the FIG. 1 embodiment in that aloop 80 of coarsely woven wire or fabric is substituted for the porousroll surface of the roll 73. The fabric '80 is supported by means ofrolls 73x, 81, 82 and 83. The roll 73x is placed in the same relation tothe roll 21 as the roll 73 in the first described embodiment; and theother parts of the machine are similar to those in the first embodimentand are given the same reference numerals but with the subscript aadded.

The roll 73x may be a solid roll and holds the fabric 80 in contact withthe external surface of the forming wire 20a preferably with asubstantial force. The roll 81 may be a simple turning roll; the roll 82may be a guide roll suitably controlled in movement at one end of theroll; and the roll 83 may be a stretch roll movable at both ends tomaintain the fabric 80 taut. The fabric 80 may consist of interwovenfilaments of either metal or synthetic organic material and essentiallymay be similar to the forming wires 20 and 20a. The fabric 80 may, forexample, be of 40 mesh, that is having 40 filaments to the inch bothtransversely and longitudinally. The fabric 80 collects water from theexternal surface or from the interstices of the wire 20 into theinterstices of the fabric 80 and the fabric 80 thus has much the samedewatering action with respect to the forming wire 20a and the webbetween the felt 36a and wire 20a as the roll 73 provided with a wirejacket on its peripheral surface has with respect to the fabric 20 andthe Web disposed between the fabric 20 and the felt 36 in the firstembodiment. The water collected by the fabric 80 is thrown from it asthe fabric passes about the rolls 81, 82 and 83.

The modified wet end section illustrated in FIG. 3 is similar to thatillustrated in FIG. 2, except that a longer fabric y, corresponding tothe fabric 80, is used; and the fabric 80y is made to wrap a portion ofthe periphery of the slice roll 21b instead of simply having a narrownip with the roll 21b. The parts of the machine illustrated in FIG. 3are similar to the correspondingly numbered parts in the first andsecond described embodiments, with the parts in the FIG. 3 embodimentbeing provided with reference numerals to which the subscript b has beenadded.

The fabric loop 80y extends around rolls 81b, 82b, 83b and an additionalroll 84, as well as around a portion of the periphery of the slice roll21b. The rolls 81b and 84 are disposed on opposite sides of the sliceroll 21b so that the fabric 80y extends around nearly 90 of the sliceroll 21b as this embodiment of the invention is illustrated. The fabric80y first contacts the surface of the fabric 20b along the line 85extending parallel with the axis of the roll 21b and leaves the fabric20b along a similar line 86 which is quote adjacent to but spaced fromthe line 72b at which the wire 20b and felt 36b leave the roll 21b. Thefabric 80y may be of the same type as the fabric 80 in the FIG. 2embodiment.

In operation, the fabric 80 removes excess water from the surface of theforming wire 20b similarly to the action of the fabric 80 in the FIG. 2embodiment, due to the contact that the fabric 80y has with the externalsurface of the forming wire 20b about the slice roll 21b, prior to theline 72b at which the fabric 20b and felt 36b leave the surface of theslice roll 21b. The fabric 80y, moreover, has an additional function ofapplying additional dewatering pressure on the paper web being formedaround the periphery of the roll 21b for a substantial are on thesurface of the slice roll 21b, this additional pressure being due to thesubstantial tension applied on to the fabric 80y and, therefore, theforce with which the fabric 80y bears on the roll 21b. This pressure bythe fabric 80y on the sandwich formed by the wire 20b, the felt 36b andthe intermediate web being dewatered, results in additional dewateringof the web with the least possible disturbance of the web within thewire-Web-felt sandwich.

The fabric 80y thus provides a second sustained stage of pressureapplication for a substantial are about the slice roll 21b to the paperweb being formed between the wire 20b and felt 36b..The first stage ofpressure application on the web, during which the pressure is relativelylow, is due to the force with which the fabric 20b itself bears on thefirst portion of the wire-web-felt sandwich just following the portionof the wire 20b bridging the rolls 29b and 21b. This pressure is due tothe tension in the forming wire 20b itself. The fabric 80y, due to thetension maintained on the fabric, also applies a force on thewire-web-felt sandwich on the arc of the roll 21b contacted by thefabric 80y, and this force in this are is added to the force due only tothe tension in the forming wire 20b. Thus, a certain pressure is appliedby the forming wire 20b in the first part of the forming area for theweb between the breast roll 29b and the line 85 at which the fabric 80yfirst contacts the wire 20b, and a higher pressure is applied in thesecond part of the forming area between the line 85 and the line 86 atwhich the fabric 80y separates from the periphery of the roll 21b.

Each of the embodiments of the invention, assuming that the rolls 73 and73x have pressure nips respectively with the rolls 21 and 21a, haveadditional water removal capacity as compared to the first twoembodiments of the invention in cases in which the rolls 73 and 73x haveno such pressure nips. These embodiments, including the first two havingsuch pressure nips, may be particularly useful for forming heavier webs,and the fabrics 20. 20a and 20b may be used with less tension than wouldotherwise be required. Also, with the second stage of pressureapplication, the slice and breast rolls may be spaced farther apart.Therefore, using the second stage of pressure application on the slicerolls, either with the rolls 73 and 73x forcefully applied on to theslice rolls, or using the fabric 80y which forcefully bears on asubstantial arc of the slice roll 21b, more stock, and stock of greaterconsistency, may be discharged into the gap between the breast and slicerolls without any rejection of the stock back toward the inlets 69, 69aand 69b. The required overall pressure for a substantial dewatering ofthe paper web being formed is, in these cases, principally supplied inthe second part of the forming area. Also, using the embodiments toapply web dewatering pressure in a second stage, webs of a given weightmay be formed at higher speeds due to the additional water removalcapacity provided in the second stage.

Thus, it is apparent that the fabric 80y, as well as the rolls 73 and73x, not only may have the function in attracting free water carried bythe forming wire of the particular embodiment; but the rolls 73 and 73x,by having pressure nips with the associated slice rolls 21 and 21a, andthe fabric 80y, in forcefully bearing on the slice roll 21b due to thetension maintained on the fabric 80y, have the additional function ofapplying additional pressure on to the paper web being dewatered in asecond part of the forming area about the slice rolls which is spacednot only from the lines at which the forming fabric and felt firstcontact the slice roll, but also from the lines at which the fabric andfelt leave the slice roll.

What is claimed is:

1. In a paper web forming machine, the combination of an endless paperweb forming fabric having interstices therethrough for draining paperstock deposited thereon, an endless felt, means for supporting andmoving said fabric and felt each in the form of a loop and including aplurality of rolls, said rolls including a slice roll and both saidfabric and felt passing around it for a substantial arc with saidforming fabric being outermost and including a second roll disposed inproximity to said slice roll having said forming fabric passing aroundit and bridging to said slice roll and also including a third rollhaving said forming fabric passing from a line of amgency with saidslice roll to the third roll, a paper stock inlet arranged to directpaper stock between said slice and second rolls so that the stock drainsthrough said forming fabric to form a web between said fabric and N dofelt which passes around said slice roll, and a fourth roll presenting aporous surface in contact with a portion of said forming fabric which issupported by said slice roll prior to said line of tangency as theforming fabric travels about said slice roll for removing water clingingto the forming fabric as it passes around said slice roll.

2. In a paper web machine, the combination of an endless paper webforming fabric having interstices therethrough for draining paper stockdeposited thereon, an endless felt, means for supporting and moving saidfabric and felt each in the form of a loop and including a plurality ofrolls, said rolls including a slice roll and both said fabric and feltpassing around it for a substantial arc with said forming fabric beingoutermost and including a second roll disposed in proximity to saidslice roll having said forming fabric passing around it and bridging tosaid slice roll and also including a third roll having said formingfabric passing from a line of tangency with said slice roll to the thirdroll, a paper stock inlet arranged to direct paper stock between saidslice and second rolls so that the stock drains through said formingfabric to form a web between said fabric and felt which passes aroundsaid slice roll, a third endless fabric having interstices therethrough,and a plurality of rolls for movably supporting said third fabric sothat a portion of it lies in contact with the outer surface of saidforming fabric on the surface of said slice roll prior to said line oftangency as the forming fabric travels around said slice roll, wherebysaid third fabric collects water clinging to said forming fabric andremoves it from the forming fabric.

References Cited UNITED STATES PATENTS 2,694,345 11/1954 Hornbostel162--352 X 3,224,928 12/1965 Lee et al. 162-303 X S. LEON BASHORE,Primary Examiner A. C. HODGSON, Assistant Examiner US. Cl. X.R.162--214, 352

